Okay. About 71% of the Earth's surface is water. And salt water holds about 96.5% of all the Earth's water. The remaining 3% of freshwater is found in Glaciers and ice caps making it difficult to use because it is frozen. Other places freshwater can be found is: Lakes, swamps, rivers and the atmosphere. I hope this helps!
The Answer D sound logical however I’m not sure about the 4 new chromosomes

When seawater seeps down into the ocean crust and is heated by the magma, it undergoes lots of chemical reactions. When the fluid rises up through the seafloor, it carries many new chemicals with it, such as-- copper and zinc.
These chemical reactions also remove chemicals from the seawater, such as oxygen and magnesium.
So clearly vebtus fluid is different from sea water .
HOPE IT HELPS YOU.